Crystal detector of electric currents



Oct. 18,1927.

H.' M. DOWSETT CRYSTAL DETECTOR or ELECTRIC cuRnEm-s Filpd Dec. 18. 1 2

Patented Oct. 18, 1927.

* UNITED STATES PATENT OFFICE.

HARRY MELVILLE DOWSETT, OF COLCHESTER, ENGLAND, ASSIGNOR T0 RADIO COR- PORATION OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

CRYSTAL DETECTOR OF ELECTRIC CURRENTS.

Application filed December 18, 1920, Serial No. 431,800, and in Great Britain February 14, 1920.

The typical crystal detector consists of a small portion of somemineral, such as carborundum, zincite, molybdenum, etc. to which an electric connection is made were wide surface on one part of it, usually by means of solder, and a second electrical connection is made at a. point on another part In the case of carborundum a welded steel or tungsten contact gives better results than one of brass or copper, and it appears that the metal employed should preferably'have a melting point equal to or greater than the temperature at which the crystal changes either its physical or chemical nature.

My invention is illustrated by the accompanying drawing which is a section through a crystal detector. A carborundum crystal 1 has welded to one end of it a piece of steel 2 and is set in solder 3 in a brass cup 4 by which it can be mounted as desired. The point connection is made between the point of the crystal and a steel plate 5. The piece of steel 2 is preferably formed on the crystal by dipping the latter into molten or semimolten metal.

It is found that the solder can be made to cover any depth of the crystal up to a'very small distance from the point contact with out affecting the characteristic given by the unmounted steel-tipped crystal.

Having now particularly described the nature of my said invention and in what manner the same is to be performed, I de clare that what I claim is I 1. A crystal detector comprising in cornbination'a crystal embedded insteel, substantially, as described.

2. In combination a detector comprising a crystal of carborundum-embedded in steel, substantially as described.

HARRY MELVILLE DOWSETT. 

